Regardless of whether it is heavy rail or light rail, steel rails are rolled from carbon killed steel smelted in open hearth and oxygen converters. Its purpose is to withstand the operating pressure and impact load of rolling stock. The rolled rails should be straight, without significant bending or twisting. The local bending and torsion of light and heavy rails, as well as the amount of correction deformation, and the inclination of rail end faces, shall not exceed the standard. The surface of steel rail should be clean and smooth, free of defects such as cracks, scars, scratches, etc.; there should be no shrinkage marks and interlayers on the end surface.